Silent, with no moving parts and virtually exhaust
free, a Power Authority-installed fuel cell supplementing the power
supply at the Westchester County Wastewater Treatment Plant in Yonkers,
New York, has one additional and remarkable distinction: It’s the first
in the world to run on anaerobic digester gas (ADG). Fuel cells normally
run on natural gas.

A byproduct of sewage treatment, ADG, if released into
the atmosphere, contributes to the “greenhouse effect,” which some
scientists believe to be a cause of global warming. Flaring, or burning
off, the gas, although mitigating the problem in recent years, also
contributes to polluting the air. NYPA installed the 200-kilowatt
Yonkers unit in 1997 to assess its environmental and economic benefits
through ongoing testing.

The Yonkers fuel cell avoids flaring of most of the ADG,
instead using it as “free” fuel to create electricity. Inside the unit,
hydrogen from the ADG reacts with oxygen from the air to create
electricity. Fuel cells are exceptionally clean and efficient. Air
emissions are much lower than from a typical fossil-fueled power plant.
A typical fuel cell powered by Anaerobic Digester gas generates about
1.6 million kilowatt-hours of electricity a year while releasing only 72
pounds of emissions into the environment. The average coal- or oil-fired
plant generating the same amount of electricity produces more than
41,000 pounds of pollutants, including almost 30,000 pounds of sulfur
oxides and 11,000 pounds of nitrous oxides.

The Yonkers installation has earned a number of awards
and international recognition.